This invention relates to the disproportionation (metathesis) of olefins. In accordance with one aspect, this invention relates to a catalyst suitable for use in the disproportionation of olefinic hydrocarbons. In accordance with another aspect, this invention relates to a process for the disproportionation of olefinic hydrocarbons. In accordance with a further aspect, this invention relates to a catalyst suitable for use in the disproportionation of olefins comprising tungsten oxide promoted with a small amount of silver. In accordance with a further aspect, this invention relates to a catalyst suitable for use in the disproportionation of olefins comprising silica and tungsten oxide promoted with silver oxide. In accordance with another aspect, this invention relates to a process for the disproportionation of olefinic hydrocarbons with a disproportionation catalyst as hereinbefore described under conditions of temperature and pressure which effect disproportionation of the feed.
The disproportionation, or metathesis, of olefins is a reaction in which one or more olefinic compounds are transformed into other olefins of different molecular weights. The disproportionation of an olefin with itself to produce an olefin of a higher molecular weight and an olefin of a lower molecular weight can also be referred to as a self-disproportionation. For example, propylene can be disproportionated to ethylene and cis-, and trans-2-butene. Another type of disproportionation involves the cross-disproportionation of two different olefins to form still other olefins. An example would be the reaction of one molecule of 2-butene with one molecule of 3-hexene to produce two molecules of 2-pentene.
By the term "disproportionation" or "metathesis" throughout this specification is meant the conversion of the feed olefinic (or unsaturated) hydrocarbon to a mixture of olefinic (or unsaturated) hydrocarbons having different numbers of carbon atoms than the feed hydrocarbons.
Among the catalysts that have been developed for disproportionation are those comprising inorganic refractory materials, such as silica, containing a catalytic amount of tungsten oxide. The present invention is based upon the discovery of a way to improve the activity of such a catalyst.
Accordingly, an object of this invention is to provide a method for the conversion of olefins.
Another object of this invention is to provide a catalyst for the conversion of olefins.
Still another object of this invention is to provide a method for converting olefins to olefins having different numbers of carbon atoms than the feed hydrocarbons.
Still another object is to provide a method for improving the activity of a disproportionation catalyst for the conversion of olefins into olefins having different numbers of carbon atoms than the feed hydrocarbons.
Other aspects, objects and the several advantages of the invention will be apparent to one skilled in the art upon reading the disclosure including a detailed description of the invention and the appended claims.